(Adds fresh quotes from NATO-led force)
KABUL, March 6 (Reuters) - Five Afghan soldiers were killed on Thursday in an air strike by the NATO-led force in Afghanistan's eastern province of Logar, Afghan officials and the coalition said.
Coalition airstrikes on friendly targets have helped widen a rift between Afghan President Hamid Karzai and the United States, cementing his resolve not to sign a bilateral security deal to let U.S. troops remain in the country after 2014.
"We condemn the attack on the Afghan National Army in Logar," said Aimal Faizi, a spokesman for Karzai. "The president has ordered an investigation."
The airstrike, at around 3.30 a.m., seriously wounded at least eight other soldiers, said district governor Khalilullah Kamal.
"Right now a discussion in the province is going on between Afghan officials and foreign forces to find out the reason for this attack," he said, describing the attack as having targeted a new outpost of the Afghan army.
A total of 17 people had been injured, his office said.
Coalition forces said soldiers were accidentally bombed during an operation intended to support Afghan security forces in the province because they were mistaken for insurgents.
"The aircraft engaged suspected insurgents on a ridge overlooking Nawer village," it said, adding the victims were later identified as Afghan army soldiers.
"We value the strong relationship with our Afghan partners, and we will determine what actions will be taken to ensure incidents like this do not happen again."
The ministry of defence said a delagation had been sent to the area to investigate.
"Dead bodies and wounded personnel have been transferred to Kabul," it added.
(Reporting by Mirwais Harooni in Kabul and Samihullah Paiwand in Gardez; Writing by Jessica Donati; Editing by Clarence Fernandez and Hugh Lawson)